1. Field of the Invention
The present invention relates to an air-conditioning system controller for controlling an air-conditioning system for cooling or heating a building such as a hospital.
2. Description of the Related Art
In recent years, there has been an increasing demand for energy saving of various types of air-conditioning equipment constituting an air-conditioning system in a building or the like. To meet this demand, a large number of air-conditioning system controllers have been proposed that can reduce the power of the air-conditioning equipment.
Many of conventional air-conditioning system controllers are based on a method in which the operating state of the air-conditioning system is changed depending on the air-conditioning load. Some following control methods are proposed.
(1) A method in which a plurality of operation modes are set in advance, optimal operation modes of the air-conditioning equipment are selected in accordance with the air-conditioning load, and the air-conditioning system is operated in the selected operation modes (e.g., Patent Document 1).
(2) A method in which the rotational rate of a compressor attached to a heat source machine is controlled in accordance with the air-conditioning load (e.g., Patent Document 2).
(3) A method in which the number of operating refrigerators is changed depending on the air-conditioning load (e.g., Patent Document 3).
(4) A method in which respective target values of coil temperatures of air-conditioning coils and chilled water temperature of a heat source machine are obtained such that the total required power of air-conditioning equipment, such as the heat source machine, water pump, and blower fans, is minimal, and thereafter, the water pump, blower fans, etc., are controlled so that the coil temperatures and chilled water temperature reach the target coil temperature values and target chilled water temperature, respectively (e.g., Patent Document 4).
Patent Document 1: Jpn. Pat. Appln. KOKAI Publication No. 2004-271095,
Patent Document 2: Jpn. Pat. Appln. KOKAI Publication No. 2006-125797.
Patent Document 3: Jpn. Pat. Appln. KOKAI Publication No. 2005-233557
Patent Document 4: Jpn. Pat. Appln. KOKAI Publication No. 2004-069134.